Intervertebral disc device employing prebent sheath

ABSTRACT

An intervertebral disc device is provided comprising a distal sheath sized to be extended from a distal end of an introducer that is percutaneously delivered into an interior of an intervertebral disc, a distal section of the sheath being predisposed to adopting a bent configuration when extended from the introducer; a probe adapted to be extended from a distal end of the sheath, the bent section of the sheath causing the probe to adopt a same bent configuration; and a proximal handle for externally guiding the probe within an intervertebral disc.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is related to co-pending application Ser. No.09/876,833, filed Jun. 6, 2001, to Kevin To et al., entitled“INTERVERTEBRAL DISC DEVICE EMPLOYING LOOPED PROBE,” and to Ser. No.09/876,832, filed Jun. 6, 2001, to Hugh Sharkey et al., entitled“INTERVERTEBRAL DISC DEVICE EMPLOYING FLEXIBLE PROVE,” and to Ser. No.09/876,831, filed Jun. 6, 2001, to Andy Uchida et al., entitled“ELECTROMAGNETIC ENERGY DELIVERY INTERVERTEBRAL DISC TREATMENT DEVICES.”

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to methods and apparatuses for accessing andmodifying intervertebral disc tissue and more particularly to accessingand modifying intervertebral disc tissue using percutaneous techniquesthat avoid major surgical intervention.

2. Description of Related Art

Intervertebral disc abnormalities have a high incidence in thepopulation and may result in pain and discomfort if they impinge on orirritate nerves. Disc abnormalities may be the result of trauma,repetitive use, metabolic disorders and the aging process and includesuch disorders but are not limited to degenerative discs (i) localizedtears or fissures in the annulus fibrosus, (ii) localized discherniations with contained or escaped extrusions, and (iii) chronic,circumferential bulging disc.

Disc fissures occur rather easily after structural degeneration (a partof the aging process that may be accelerated by trauma) of fibrouscomponents of the annulus fibrosus. Sneezing, bending or just attritioncan tear these degenerated annulus fibers, creating a fissure. Thefissure may or may not be accompanied by extrusion of nucleus pulposusmaterial into or beyond the annulus fibrosus. The fissure itself may bethe sole morphological change, above and beyond generalized degenerativechanges in the connective tissue of the disc. Even if there is novisible extrusion, biochernicals within the disc may still irritatesurrounding structures. Disc fissures can be debilitatingly painful.Initial treatment is symptomatic, including bed rest, pain killers andmuscle relaxants. More recently, spinal fusion with cages have beenperformed when conservative treatment did not relieve the pain. Thefissure may also be associated with a herniation of that portion of theannulus.

With a contained disc herniation, there are no free nucleus fragments inthe spinal canal. Nevertheless, even a contained disc herniation isproblematic because the outward protrusion can press on the spinalnerves or irritate other structures. In addition to nerve rootcompression, escaped nucleus pulposus contents may chemically irritateneural structures. Current treatment methods include reduction ofpressure on the annulus by removing some of the interior nucleuspulposus material by percutaneous nuclectomy. However, complicationsinclude disc space infection, nerve root injury, hematoma formation,instability of the adjacent vertebrae and collapse of the disc fromdecrease in height.

Another disc problem occurs when the disc bulges outwardcircumferentially in all directions and not just in one location. Overtime, the disc weakens and takes on a “roll” shape or circumferentialbulge. Mechanical stiffness of the joint is reduced and the joint maybecome unstable. One vertebra may settle on top of another. This problemcontinues as the body ages and accounts for shortened stature in oldage. With the increasing life expectancy of the population, suchdegenerative disc disease and impairment of nerve function are becomingmajor public health problems. As the disc “roll” extends beyond thenormal circumference, the disc height may be compromised, foramina withnerve roots are compressed. In addition, osteophytes may form on theouter surface of the disc roll and further encroach on the spinal canaland foramina through which nerves pass. The condition is called lumbarspondylosis.

It has been thought that such disc degeneration creates segmentalinstability which disturbs sensitive structures which in turn registerpain. Traditional, conservative methods of treatment include bed rest,pain medication, physical therapy or steroid injection. Upon failure ofconservative therapy, spinal pain (assumed to be due to instability) hasbeen treated by spinal fusion, with or without instrumentation, whichcauses the vertebrae above and below the disc to grow solidly togetherand form a single, solid piece of bone. The procedure is carried outwith or without discectomy. Other treatment include discectomy alone ordisc decompression with or without fusion. Nuclectomy can be performedby removing some of the nucleus to reduce pressure on the annulus.However, complications include disc space infection, nerve root injury,hematoma formation, and instability of adjacent vertebrae.

These interventions have been problematic in that alleviation of backpain is unpredictable even if surgery appears successful. In attempts toovercome these difficulties, new fixation devices have been introducedto the market, including but not limited to pedicle screws and interbodyfusion cages. Although pedicle screws provide a high fusion successrate, there is still no direct correlation between fusion success andpatient improvement in function and pain. Studies on fusion havedemonstrated success rate of between 50% and 67% for pain improvement,and a significant number of patients have more pain postoperatively.Therefore, different methods of helping patients with degenerative discproblems need to be explored.

One of the challenges associated with treating intervertebral discs isaccessing them via percutaneous methods. To appreciate the difficultypresented, the anatomical structure of the spine and an intervertebraldisc is illustrated and described below.

FIGS. 1A and 1B illustrate a cross-sectional anatomical view of avertebra and associated disc and a lateral view of a portion of a lumbarand thoracic spine, respectively. Structures of a typical cervicalvertebra (superior aspect) are shown in FIG. 1A: 104—lamina; 106—spinalcord; 108—dorsal root of spinal nerve; 114—ventral root of spinal nerve;115—posterior longitudinal ligament; 118—intervertebral disc;120—nucleus pulposus; 122—annulus fibrosus; 124—anterior longitudinalligament; 126—vertebral body; 128—pedicle; 130—vertebral artery;132—vertebral veins; 134—superior articular facet; 136—posterior lateralportion of the annulus; 138—posterior medial portion of the annulus; and142—spinous process. In FIG. 1A, one side of the intervertebral disc 118is not shown so that the anterior vertebral body 126 can be seen.

FIG. 1B is a lateral aspect of the lower portion of a typical spinalcolumn showing the entire lumbar region and part of the thoracic regionand displaying the following structures: 162—intervertebral disc;142—spinous process; 168—inferior articular process; 170—inferiorvertebral notch; 174—superior articular process; 176—lumbar curvature;and 180—sacrum.

The presence of the spinal cord and the posterior portion of thevertebral body, including the spinous process, and superior and inferiorarticular processes, prohibit introduction of a needle or trocar from adirectly posterior position. This is important because the posteriordisc wall is the site of symptomatic annulus tears and discprotrusions/extrusions that compress or irritate spinal nerves for mostdegenerative disc syndromes.

FIG. 1C provides a posterior-lateral anatomical view of two lumbarvertebrae and illustration of the triangular working zone. The inferiorarticular process 168, along with the pedicle 128 and the lumbar spinalnerve 110, form a small “triangular” window through which introductionof an instrument can be achieved from the posterior lateral approach.FIG. 1D illustrates an instrument (an introducer 169) introduced into anintervertebral disc by the posterior lateral approach.

FIG. 1E illustrates the anatomy of an intervertebral disc in greaterdetail and shows an introducer 169 inserted into the disc. Structures ofthe disc are identified and described by these anatomical designations:the posterior lateral inner annulus 136, posterior medial inner annulus138, annulus fibrosus 122/nucleus pulposus 120 interface, theannulus/dural interface 146, annulus/posterior longitudinal ligamentinterface 148, anterior lateral inner annulus 150, and the anteriormedial inner annulus 152.

The annulus fibrosus 122 is comprised primarily of tough fibrousmaterial, while the nucleus pulposus 120 is comprised primarily of anamorphous colloidal gel. There is a transition zone between the annulusfibrosus 122 and the nucleus pulposus 120 made of both fibrous-likematerial and amorphous colloidal gel. The border between the annulusfibrosus 122 and the nucleus pulposus 120 becomes more difficult todistinguish as a patient ages, due to degenerative changes. This processmay begin as early as 30 years of age. For purposes of thisspecification, the inner wall of the annulus fibrosus can include theyoung wall comprised primarily of fibrous material as well as thetransition zone which includes both fibrous material and amorphouscolloidal gels (hereafter collectively referred to as the “inner wall ofthe annulus fibrosus”). Functionally, the location at which there is anincrease in resistance to probe penetration and which is sufficient tocause bending of the distal portion of the probe into a radius less thanthat of the internal wall 22 of the annulus fibrosus is considered to bethe “inner wall of the annulus fibrosus”.

As with any medical instrument and method, not all patients can betreated, especially when their disease or injury is too severe. There isa medical gradation of degenerative disc disease (stages 1-5). See, forexample, Adams et al., “The Stages of Disc Degeneration as Revealed byDiscograms,” J. Bone and Joint Surgery, 68, 36-41 (1986). As thesegrades are commonly understood, the methods of instrument navigationdescribed herein would probably not be able to distinguish between thenucleus and the annulus in degenerative disease of grade 5. In any case,most treatment is expected to be performed in discs in stages 3 and 4,as stages 1 and 2 are asymptomatic in most patients, and stage 5 mayrequire disc removal and fusion.

It is well known to those skilled in the art that percutaneous access tothe disc is achieved by placing an introducer into the disc from thisposterior lateral approach, but the triangular window does not allowmuch room to maneuver. Once the introducer pierces the tough annulusfibrosus, the introducer is fixed at two points along its length and hasvery little freedom of movement. Thus, with the exception of devicessuch as those described in U.S. Pat. Nos. 6,135,999; 6,126,682;6,122,549; 6,099,514; 6,095,149; 6,073,051; 6,007,570; 5,980,504 (whichare each incorporated herein by reference), the posterior lateralapproach has only allowed access to small central and anterior portionsof the nucleus pulposus.

The present invention provides devices and methods which are designed tomore efficiently access and treat the interior of intervertebral discsby the posterior lateral approach.

SUMMARY OF THE INVENTION

The present invention relates to various embodiments of intervertebraldisc devices and their methods of use.

According to one embodiment, the intervertebral disc device comprises adistal probe sized to be extended from a distal end of an introducerthat is percutaneously delivered into an interior of an intervertebraldisc, a distal section of the probe comprising a flexible neck whichtapers in a proximal to distal direction, and a distal tip which islarger in cross sectional diameter than the flexible neck adjacent thedistal tip, the flexible neck and distal tip serving to prevent theprobe distal end from piercing an internal wall of the intervertebraldisc; and a proximal handle for externally guiding the probe within anintervertebral disc.

The flexible neck may optionally be designed such that it is notpredisposed to bending in any direction relative to a longitudinal axisof the probe. Alternatively, the flexible neck may be designed to bepredisposed to bending along a single plane relative to a longitudinalaxis of the probe. Alternatively, the flexible neck may be designed tobe predisposed to bending in opposing directions along a single planerelative to a longitudinal axis of the probe. Alternatively, theflexible neck may be designed to be predisposed to bending in at leasttwo different directions along at least two different planes relative toa longitudinal axis of the probe.

According to this embodiment, the flexible neck may optionally have around cross section. Alternatively, or in addition, the flexible neckmay optionally have at least one flat surface extending along alongitudinal axis of the neck. In one variation, the flexible neck hastwo flat surfaces extending along a longitudinal axis of the neck onopposing sides of the neck.

Also according to this embodiment, the neck may optionally be formed ofa flexible coil.

According to this embodiment, the distal tip may optionally have alarger cross sectional diameter than a largest cross sectional diameterof the flexible neck. The distal tip may be symmetrical or asymmetrical.In certain variations, the distal tip is dome shaped or has a flatsurface perpendicular to a longitudinal axis of the probe.

The distal tip may be attached to the neck of the probe by a variety ofmechanisms including, for example, a spring or a pivot mechanism such asa ball and socket mechanism.

In one preferred variation, the flexibility of the neck of the probe isdesigned such that it causes the probe to bend and the distal tip totrail behind a portion of the probe as the probe is advanced throughtissue within an intervertebral disc. The shape of the distal tip mayalso contribute to the distal tip trailing behind a portion of theprobe.

In another embodiment, an intervertebral disc device is providedcomprising: a distal probe sized to be extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the probe comprising an activeelectrode and a return electrode which are each spirally wrapped aroundthe probe such that there are multiple alternating bands of the sameactive and return electrodes positioned longitudinally along the lengthof the distal section of the probe, the active and return electrodesbeing adapted to deliver bipolar electromagnetic energy to tissue withinthe intervertebral disc; and a proximal handle for externally guidingthe probe within an intervertebral disc.

According to this embodiment, the distal section of the probe may bepredisposed to forming a loop.

In another embodiment, an intervertebral disc device is providedcomprising: a distal probe sized to be extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the probe being predisposed toforming a loop when extended from the distal end of the introducer, thelooping portion of the probe comprising an active electrode and a returnelectrode which are positioned on the probe such that the active andreturn electrodes are on opposing sides of the probe loop; and aproximal handle for externally guiding the probe within anintervertebral disc.

In yet another embodiment, an intervertebral disc device is providedcomprising: a distal probe sized to be extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the probe comprising separateactive and return electrode elements which are predisposed to bendingaway from each other when extended from the distal end of theintroducer; and a proximal handle for externally guiding the probewithin an intervertebral disc.

In another embodiment, an intervertebral disc device is providedcomprising: a distal sheath sized to be extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the sheath being predisposed toadopting a bent configuration when extended from the introducer; a probeadapted to be extended from a distal end of the sheath, the bent sectionof the sheath causing the probe to adopt a same bent configuration; anda proximal handle for externally guiding the probe within anintervertebral disc.

In another embodiment, an intervertebral disc device is providedcomprising: a distal sheath sized to be extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the sheath being predisposed toadopting a bent configuration when extended from the introducer; a guidewire adapted to be extended from a distal end of the sheath, the bentsection of the sheath causing the guide wire to adopt a same bentconfiguration; a probe adapted to be extended from a distal end of thesheath over the guide wire, the bent section of the sheath causing theprobe to adopt a same bent configuration; and a proximal handle forexternally guiding the probe within an intervertebral disc.

According to one variation of this embodiment, a distal section of theprobe comprises an active electrode and a return electrode which areeach spirally wrapped around the probe such that there are multiplealternating bands of the same active and return electrodes positionedlongitudinally along the length of the distal section of the probe, theactive and return electrodes being adapted to deliver bipolarelectromagnetic energy to tissue within the intervertebral disc.Optionally, the distal section of the probe may be predisposed toforming a loop. When the distal section of the probe is predisposed toforming a loop when extended from the distal end of the introducer, thelooping portion of the probe may comprise an active electrode and areturn electrode which are positioned on the probe such that the activeand return electrodes are on opposing sides of the probe loop.

According to another variation of this embodiment, a distal section ofthe probe comprises separate active and return electrode elements whichare predisposed to bending away from each other when extended from thedistal end of the introducer.

In another embodiment, an intervertebral disc device is providedcomprising: a probe capable of being extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, the probe forming a loop when extended from thedistal end of the introducer, the loop having first and second proximalends external to the introducer which are brought together adjacent theintroducer distal end to form the loop by the proximal ends being eitherattached to or entering the distal end of the introducer; and a proximalhandle for externally causing the probe to be extended from the distalend of the introducer and externally guiding the probe within anintervertebral disc.

According to this embodiment, the device may optionally further includean introducer, the first proximal end of the probe being attached to theintroducer adjacent a distal end of the introducer, the second proximalend of the probe being extendable from the introducer distal end to formthe loop. According to this variation, the first proximal end of theprobe may optionally be attached to the introducer adjacent the distalend of the introducer by a guide wire lead. Alternatively, the first andsecond proximal ends of the probe may each be separately extendable fromthe introducer distal end to form the loop. When the first and secondproximal ends of the probe are each separately extendable from theintroducer distal end to form the loop, the first and second proximalends of the probe may have different cross sectional geometries.According to this variation, the different cross sectional geometries ofthe first and second proximal ends may be selected such that the crosssectional geometry of the first proximal end is a compliment of thecross sectional geometry of the second proximal end.

In another embodiment, an intervertebral disc device is providedcomprising: a guide wire capable of being extended from a distal end ofan introducer that is percutaneously delivered into an interior of anintervertebral disc, the guide wire forming a loop when extended fromthe distal end of the introducer, the loop having first and secondproximal ends external to the introducer which are brought togetheradjacent the introducer distal end to form the loop by the proximal endsbeing either attached to or entering the distal end of the introducer; aprobe capable of being extended over the guide wire from the distal endof the introducer; and a proximal handle for externally causing theguide wire and probe to be extended from the distal end of theintroducer and externally guiding the guide wire and probe within anintervertebral disc.

In one variation of this embodiment, the device further includes anintroducer, the first proximal end of the guide wire being attached tothe introducer adjacent a distal end of the introducer, the secondproximal end of the guide wire being extendable from the introducerdistal end to form the loop. In another variation, the first and secondproximal ends of the guide wire are each separately extendable from theintroducer distal end to form the loop.

In another embodiment, an intervertebral disc device is providedcomprising: guide wire capable of being extended from a distal end of anintroducer that is percutaneously delivered into an interior of anintervertebral disc, a distal section of the guide wire beingpredisposed to forming a loop when extended from the distal end of theintroducer, the looped distal section of the guide wire serving tolocalize the looped distal section within the intervertebral disc; aprobe capable of being extended over the guide wire from the distal endof the introducer, the probe and guide wire being extendable incombination such that position of the looped distal section of the guidewire is not changed; and a proximal handle for externally causing theguide wire and probe to be extended from the distal end of theintroducer and externally guiding the guide wire and probe within anintervertebral disc.

According to any of the above embodiments, the device may furtherinclude flexible tubing operably interconnecting the proximal handlewith the distal probe. The probe and/or guide wire may optionally extendwithin the flexible tubing to the handle.

Also according to any of the above embodiments, the device may furtherinclude a connector system which enables an introducer to be removeablyattached to the connector system, the probe being positionable withinthe introducer for delivery within the intervertebral disc with theassistance of the introducer.

According to any of the above embodiments, the device may furtherinclude a probe or guide wire with a mechanism for securing the probe orguide wire within the selected section of the intervertebral disc. Themechanism may be a curved portion adjacent the distal end capable ofanchoring the probe or guide wire into tissue. The curved distal portionpreferably forms a distal end of the probe or guide wire. The curveddistal portion is optionally retractable and optionally divides intomultiple separate curved portions, such as to form a treble hook.

Also according to any of the above embodiments, the probe may furtherinclude a functional element which performs a function. A wide varietyof functions may be performed by the functional element including, butnot limited to, transmitting energy to tissue within an intervertebraldisc, delivering material to within an intervertebral disc, and removingmaterial within an intervertebral disc.

When the function element transmits energy, the probe may furtherinclude an electromagnetic energy device capable of supplying energywithin the intervertebral disc. The electromagnetic energy device may becapable of delivering energy selected from group consisting of coherentand incoherent light and radiofrequency (RF), microwave, and ultrasoundwaves. When delivering RF energy, the electromagnetic energy devicecomprises electrodes adapted to deliver RF energy. The RF electrodes mayadopt a monopolar or bipolar configuration. The electromagnetic energydevice may also comprise a resistive heating mechanism.

Also according to any of the above embodiments, the handle may furthercomprise a probe control element for controlling the movement of theprobe adjacent a distal end of the device. The device may also comprisea guide wire control element for controlling the movement of the guidewire adjacent a distal end of the device.

Methods are also provided for employing the various devices of thepresent invention to treat an interior of an intervertebral disc.

In one embodiment, the method comprises inserting an introducer througha skin of a person such that the distal end of the introducer travelswithin the person via a posterior lateral approach to an intervertebraldisc such that a distal end of the introducer is positioned in oradjacent an intervertebral disc; extending a probe from a distal end ofthe introducer such that the probe is positioned within theintervertebral disc; and treating tissue within the interior of theintervertebral disc using the probe. The probe that is extended from theintroducer may have any of the various probe designs described herein.

In another embodiment, the method comprises inserting an introducerthrough a skin of a person such that the distal end of the introducertravels within the person via a posterior lateral approach to anintervertebral disc such that a distal end of the introducer ispositioned in or adjacent an intervertebral disc; extending a guide wirefrom a distal end of the introducer such that the guide wire ispositioned within the intervertebral disc; extending a probe over theguide wire, and treating tissue within the interior of theintervertebral disc using the probe. The guide wire and probe that areextended from the introducer may have any of the various guide wire andprobe designs described herein.

In another embodiment of the invention, a method for delivering a probeis provided. The method comprises extending a guide wire into anintervertebral disc such that the guide wire is positioned within theintervertebral disc adjacent an inner wall of the disc; attaching adistal portion of the guide wire to the inner wall; and extending aprobe over the guide wire. The guide wire and probe that are extendedmay have any of the various guide wire and probe designs describedherein.

According to this embodiment, the step of attaching the distal portionof the guide wire may be accomplished by inserting a portion of theguide wire into the tissue of the inner wall of an intervertebral discsuch that the distal portion is held in place and retained by the tissueof the inner wall of the disc. In this regard, a variety of attachmentmechanisms may be employed. For example, the step of attaching thedistal portion of the guide wire may be by hooking the attachmentmechanism into the tissue of the inner wall such that the distal portionis held in place and retained by the tissue of the inner wall of thedisc. The attachment mechanism may be a curved distal portion of theguide wire.

All of the above embodiments involving attaching the guide wire to theinner wall of an intervertebral disc may be adapted where the probeinstead of the guide wire comprises an attachment mechanism forattaching the probe to the inner wall.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A provides a superior cross-sectional anatomical view of acervical disc and vertebra.

FIG. 1B provides a lateral anatomical view of a portion of a lumbarspine.

FIG. 1C provides a posterior-lateral anatomical view of two lumbarvertebrae and illustration of the triangular working zone.

FIG. 1D provides a superior cross-sectional view of the requiredposterior lateral approach.

FIG. 1E illustrates the anatomy of an intervertebral disc in greaterdetail and shows an introducer inserted into the disc.

FIG. 2 illustrates an embodiment of an intervertebral disc devicesystem.

FIG. 3A illustrates a distal section of a probe with a flexible neck anda blunt distal tip.

FIG. 3B illustrates a sequence demonstrating the flexing of the flexibleneck of the probe.

FIG. 3C illustrates a distal section of a probe with a rounded neck.

FIG. 3D illustrates a neck which has been flattened on one side.

FIG. 3E illustrates a neck which has been flattened on two opposingsides.

FIG. 3F illustrates a neck where the neck is formed of a coil.

FIGS. 4A-4C illustrate a series of different distal tips which may beattached to the distal sections of the probes employed in the devices ofthe present invention.

FIG. 4A illustrates a dome shaped distal tip where the distal tip issymmetrical about the longitudinal axis of the distal section of theprobe.

FIG. 4B illustrates an offset dome shaped distal tip where the distaltip is asymmetrical about the longitudinal axis of the distal section ofthe probe.

FIG. 4C illustrates an flat distal tip.

FIGS. 5A-5C illustrate a series of different distal tip attachmentmechanisms which may be used to attach a distal tip to a distal sectionof a probe employed in the devices of the present invention.

FIG. 5A illustrates an embodiment where the distal tip and the neck ofthe distal section is one unit made of the same material.

FIG. 5B illustrates an embodiment where the distal tip and the neck ofthe distal section are attached to each other by a pivot mechanism.

FIG. 5C illustrates an embodiment where the distal tip and the neck ofthe distal section are attached to each other by a spring.

FIG. 6 illustrates movement with bending of a distal section withinnucleous pulposus as the distal section of the device is advanced withinthe intervertebral disc.

FIGS. 7A-7C illustrate a sequence which shows how tissue force resistingthe forward advancement of the probe within the intervertebral disccauses the distal section of the probe to bend.

FIG. 7A shows a probe with an asymmetrical distal tip.

FIG. 7B illustrates that the asymmetrical resistance causes the distalsection of the probe to bend.

FIG. 7C illustrates that further bending of the probe causes tissueforce to be applied to the back of the distal tip as the distal sectionis advanced further.

FIGS. 8A-8Q illustrate a series of different embodiments for deployingthe distal section of the probe from the introducer so that the probeapproaches the internal wall of the annulus fibrosus.

FIG. 8A illustrates an embodiment where the distal end of the probe isattached to the distal end of the introducer.

FIG. 8B illustrates that the probe shown in FIG. 8A may be extended outof the distal end of the introducer to cause the probe to form a loop.

FIG. 8C illustrates another embodiment where the distal end of the probeis attached to the distal end of the introducer via a guide wire lead.

FIG. 8D illustrates that the probe shown in FIG. 8C may be extended outof the distal end of the introducer to cause the probe to form a loop.

FIG. 8E illustrates another embodiment where the distal end of the probeforms a loop within the introducer where both sides of the probe areseparately extendable and retractable relative to the distal end of theintroducer.

FIG. 8F illustrates that the probe shown in FIG. 8E may be extended outof the distal end of the introducer to cause the probe to form a loop.

FIG. 8G illustrates another embodiment where a guide wire is attached tothe distal end of the introducer.

FIG. 8H illustrates the extension of a guide wire.

FIG. 8I illustrates that the probe shown in FIG. 8G may be extendedalong the guide wire out of the distal end of the introducer.

FIG. 8J illustrates another embodiment where a guide wire forms a loopwithin the introducer where both sides of the guide wire loop areseparately extendable and retractable relative to the distal end of theintroducer.

FIG. 8K illustrates that extension of the guide wire shown in FIG. 8Jout of the distal end of the introducer causes the guide wire to form aloop.

FIG. 8L illustrates that a probe may be extended along the guide wireshown in FIG. 8K out of the distal end of the introducer.

FIGS. 8M-8O illustrate another embodiment of the embodiment shown inFIG. 8J where the guide wire is capable of being folded upon itself.

FIG. 8M illustrates the guide wire unfolded where section I includes aguide wire with a thin, concave shape, section II includes a taperedsection that provides an area where the guide wire is folded uponitself, and section III includes a rounded section such that the roundedsection fits within the concave shape of section I.

FIG. 8N shows the cross sections of guide wire sections I-IIIillustrated in FIG. 8M.

FIG. 8O illustrates that the guide wire may be folded upon itself wherethe crease is at section II, and section I and section III cometogether.

FIG. 8P provides a sequence illustrating the deployment of the guidewire from an introducer within a disc such that the guide wire encirclesthe internal wall of the disc.

FIG. 8Q illustrates yet another embodiment where a guide wire and probeare used in combination to deploy the probe adjacent an internal wall ofa disc.

FIGS. 9A-9C illustrate one embodiment where a sheath having a predefinedcurvature adjacent its distal end introduces curvature to a guide wireor probe extended from the sheath.

FIG. 9A illustrates the distal end of an introducer with a sheath and aprobe extending from the introducer.

FIG. 9B illustrates the sheath being extend from the distal end of theintroducer.

FIG. 9C illustrates the probe being extended beyond the sheath.

FIGS. 10A-10C illustrate a series of preferred designs for thermalenergy delivery devices which may be used in combination with thedevices of the present invention.

FIG. 10A illustrates an embodiment where the thermal energy deliverydevice is a bipolar electrode comprising an active electrode and areturn electrode where the active and return electrodes are eachspirally wrapped around a portion of the distal section of the probe.

FIG. 10B illustrates another embodiment of a thermal energy deliverydevice where the active and return electrodes are positioned on opposingsides of the loop.

FIG. 10C illustrates another embodiment of a thermal energy deliverydevice.

FIGS. 11A and 11B illustrate yet another embodiment for a thermal energydelivery device which may be used in combination with the devices of thepresent invention.

FIG. 11A illustrates an embodiment where a pair of probes which form areturn electrode and an active electrode extend from an introducer orsheath and are spaced apart from each other.

FIG. 11B illustrates a variation on the embodiment shown in FIG. 11Awhere the pair of probes which form an active electrode and returnelectrode diverge from each other adjacent their distal ends.

FIG. 12 shows an embodiment of the guide wire with an attachmentmechanism at the distal tip for attaching the guide wire to the innerwall of the intervertebral disc.

DETAILED DESCRIPTION

The present invention provides methods and devices for accessing andtreating intervertebral discs. In general, the devices according to thepresent invention are externally guidable percutaneous intervertebraldisc devices. As such, these devices are used to traverse the patent'sskin and access an intervertebral disc through the tissue positionedbetween the patient's skin and the intervertebral disc. Entry into theintervertebral disc is achieved by a posterior lateral approach.

1. Overview of the Intervertebral Disc Treatment Device

FIG. 2 illustrates an embodiment of an overall system for treatingintervertebral discs which incorporates devices of the presentinvention. It is noted that many of the subcomponents of the devices ofthe present invention, as well as their operation are described infurther detail in U.S. Pat. Nos. 6,135,999; 6,126,682; 6,122,549;6,099,514; 6,095,149; 6,073,051; 6,007,570; 5,980,504, which are eachincorporated herein by reference.

FIG. 2 depicts but one embodiment of the overall system. It should benoted that systems incorporating the devices of the invention can beprepared in a number of different forms and can consist (for example) ofa single instrument with multiple internal parts or a series ofinstruments that can be replaceably and sequentially inserted into ahollow fixed instrument (such as a needle) that guides the operationalinstruments to a selected location within the intervertebral disc.Because prior patents do not fully agree on how to describe parts ofpercutaneous instruments, terminology with the widest common usage willbe used.

As illustrated in FIG. 2, the proximal end 210 of the system comprises ahandle 212 which includes a guide wire control element 214 forcontrolling the movement of a guide wire adjacent a distal end 218 ofthe device and a probe body control element 216 for controlling themovement of a probe (not shown) adjacent the distal end 218 of thedevice. The handle 212 further includes one or more mechanisms 224 (notshown in detail) for attaching different external tools (e.g., energysources, material delivery and removal mechanisms (e.g., a pump),visualization tools, etc.) to the device.

Flexible tubing 226 attaches the handle 212 to a connector system 228which remains external to the body. As illustrated, the connector system228 may allow different external tools to be attached to the device. Inthis case a fluid injection tool 232 is depicted. A probe and a guidewire may optionally extend from a distal portion of the device throughthe flexible tubing to the handle. Alternatively, only mechanisms forcontrolling the probe and guide wire may extend from the distal portionof the device through the flexible tubing to the handle.

Insertion of flexible tubing between the handle 212 and the connectorsystem 228 serves to physically isolate movements of the handle 212 fromthe portion of the device which is inserted into the patient. As aresult, the patient is less prone to perceive a manipulation of thedevice within the patient as a result of movement of the handle.

The distal portion of the devices of the present invention may bedelivered through the skin of a patient and into an intervertebral discusing techniques typical of percutaneous interventions. The connectorsystem 228 allows an introducer 230 to be removably coupled to thedevice to facilitate delivery of the distal portion of the devicethrough a patient's skin to within an intervertebral disc. Asillustrated, a luer fitting 234 may be used as the attachment mechanismfor the introducer.

The term introducer is used herein to indicate that the device of theinvention can be used with any insertional apparatus that providesproximity to the disc, including many such insertional apparatuses knownin the art. An introducer has an internal introducer lumen with a distalopening 238 at a terminus of the introducer to allow insertion (andmanipulation) of the operational parts of the device into (and in) theinterior of a disc.

The introducer, in its simplest form, can consist of a hollowneedle-like device (optionally fitted with an internal removableobturator or trocar to prevent clogging during initial insertion) or acombination of a simple exterior cannula that fits around a trocar. Theresult is essentially the same: placement of a hollow tube (the needleor exterior cannula after removal of the obturator or trocar,respectively) through skin and tissue to provide access into the annulusfibrosus. The hollow introducer acts as a guide for introducinginstrumentation. More complex variations exist in percutaneousinstruments designed for other parts of the body and can be applied todesign of instruments intended for disc operations. Examples of suchobturators are well known in the art. A particularly preferredintroducer is a 17- or 18-gauge, thin-wall needle with a matchedobturator, which after insertion is replaced with a probe of the presentinvention.

The devices of the present invention further include a probe 236 whichmay be extended and retracted relative to the distal opening 238 of theintroducer 230. For example, a distal section of the probe 236 is shownto be retracted into the introducer in FIG. 2 (above) as well asextended from the distal end of the introducer (below). When extendedfrom the introducer 230, the probe 236 is intended to be located insidethe disc.

As illustrated in FIG. 1E, the introducer 169 pierces the annulusfibrosus 122 and is advanced through the wall of the annulus fibrosusinto the nucleus pulposus 120. The introducer 169 is extended a desireddistance into nucleus pulposus 120. Once the introducer 169 ispositioned within the nucleus pulposus 120, the distal section of theprobe 236 is advanced through a distal end of introducer 169 intonucleus pulposus 120.

It is noted that many probe devices access a section of tissue in thepatient's body by being delivered within the lumen of a body vessel suchas a vein or artery. Although the devices of the present invention aresaid to include a probe, the devices of the present invention do notrely upon accessing a section of tissue in the patient's body by beingdelivered within the lumen of a body vessel. Rather, “probe” is usedherein to describe the distal portion of the device which is extendedinto the intervertebral disc from the introducer.

The probe may optionally include functional elements which performdifferent functions, such as transmitting energy and/or material from alocation external to the body to a location internal to the disc beingaccessed upon. Alternatively, material can be transported in the otherdirection to remove material from the disc, such as removing material byaspiration. The device allows the functional elements to be controllablypositioned and manipulated within the guided by manipulation of thehandle.

The probe is adapted to slidably advance through the introducer lumen,the probe having a distal section which is extendible through the distalopening at the terminus of the introducer into the disc. Although thelength of the distal section can vary with the intended function of thedevice, as explained in detail below, a typical distance of extension isat least one-half the diameter of the nucleus pulposus, preferably inthe range of one-half to one and one-half times the circumference of thenucleus.

In order that the functional elements of the probe can be readily guidedto the desired location within a disc, the distal section of the probeis manufactured with sufficient rigidity to avoid collapsing upon itselfwhile being advanced through the nucleus pulposus. The distal section,however, has insufficient rigidity to puncture the annulus fibrosusunder the same force used to advance the probe through the nucleuspulposus and around the inner wall of the annulus fibrosus. Absolutepenetration ability will vary with sharpness and stiffness of the distaltip of the distal section, but in all cases, a probe of the presentinvention will advance more readily through the nucleus pulposus thanthrough the annulus fibrosus.

The inability of the distal section of the probe to pierce the annuluscan be the result of either the shape of the distal tip of the probeand/or the flexibility of distal portion. The distal tip is consideredsufficiently blunt when it does not penetrate the annulus fibrosus butis deflected back into the nucleus pulposus or to the side around theinner wall of the annulus when the distal tip is advanced. Several noveldistal tip embodiments are described herein.

2. Design Features of Intervertebral Disc Devices

The devices according to the present invention comprise multiple novelfeatures including, but not being limited to (a) flexible necks adjacentthe distal ends of the devices, (b) distal tips which facilitatenavigation of the device within an intervertebral disc, (c) attachmentmechanisms for the distal tips to the necks, (d) energy deliverymechanisms used with the devices for treating intervertebral discs, and(e) mechanisms for deploying the probe distal end within anintervertebral disc. Each of these different novel features aredescribed herein.

One feature of the probe employed in the device of the present inventionis the inability of the distal section of the probe to pierce theannulus. This may be achieved either by the design of the neck of theprobe, (i.e., the section of the distal section proximal to the distaltip) or by the design of the distal tip of the probe. The design of theneck and distal tip of the probe can also be utilized to facilitatenavigation of the device within the intervertebral disc.

FIG. 3A shows a distal section 310 of a probe with a flexible neck 312which tapers from a proximal portion 314 of the distal section. A bluntdistal tip 316 is positioned on a distal end of the distal section 310.Also illustrated is the distal end of an introducer 318 from which theprobe distal section extends. It is noted that the probe distal sectionis preferably retractable and extendable 320 relative to the distal endof the introducer.

FIG. 3B illustrates a sequence which shows how the forward advancementof the distal section 310 of a probe from an introducer 318 againsttissue causes the probe to bend at the neck 312 relative to thelongitudinal axis 324 of the distal section 310. As illustrated in thesequence, further extension 320 of the probe against the tissue causesthe distal section 310 of the probe to bend further relative to thelongitudinal axis 324 of the distal section 310.

Rendering the neck flexible can be accomplished by using a series ofdifferent neck designs, any of which may be employed in the presentinvention. For example, FIG. 3C illustrates an embodiment where the neck312 is rounded. By employing a rounded neck 312, the distal sectionexhibits no predisposition with regard to the direction in which theneck bends, as indicated by the arrows. Hence, by using a rounded astapered end, bending in any direction relative to the longitudinal axisof the distal section can be achieved.

By contrast, FIG. 3D illustrates a neck 312 which has been flattened onone side 322. Flattening the neck on one side causes the distal sectionto be predisposed to bending in the plane perpendicular to the flattenedsurface toward the side of the flattened surface. Hence, by using a neckwith a tapered end having one flat surface, the neck is predisposed tobend in a particular direction relative to the longitudinal axis of thedistal section.

FIG. 3E illustrates a neck 312 which has been flattened on two opposingsides 324, 326. Flattening the neck on the two opposing sides causes thedistal section to be predisposed to bending in planes perpendicular tothe two flattened surfaces. If both flattened surfaces are parallel toeach other, the neck will preferentially bend in the same plane (asillustrated). If the two flattened surfaces are not parallel to eachother, the neck will preferentially bend in the plane perpendicular tothe first flattened surface or the plane perpendicular to the secondflattened surface.

FIG. 3F illustrates a neck 312 where the neck is formed of a coil. Thecoil neck, like the rounded neck, allows the distal section to bend withno predisposition with regard to which direction the neck bends. Hence,by using a coiled neck, bending in any direction relative to thelongitudinal axis of the distal section can be achieved.

FIGS. 4A—4C illustrate a series of different distal tips which may beattached to the distal sections of the probes employed in the devices ofthe present invention.

FIG. 4A illustrates a dome shaped distal tip 412 where the dome issymmetrical about the longitudinal axis of the distal section of theprobe. By having the tip be dome shaped, the tip has less resistancewhen being pushed through the nucleous pulposus. Meanwhile, by causingthe distal tip to be symmetrical, the distal tip does not introduce apredisposition for the distal section to bend in any particulardirection.

FIG. 4B illustrates an offset dome shaped distal tip 414 where the domeis asymmetrical about the longitudinal axis of the distal section of theprobe. By causing the distal tip to be asymmetrical, the distal tipintroduces a predisposition for the distal section to bend on the sideof the tip where the tip is larger.

FIG. 4C illustrates a flat distal tip 416. By causing the distal tip tobe flat, the resistance felt by the distal tip when pushed through thenucleous pulposus is enhanced. Optionally, although not shown, apredisposition for the distal section to bend in a particular directioncan be imparted by designing the distal tip to be asymmetrical relativeto the longitudinal axis of the distal section.

FIGS. 5A-5C illustrate a series of different distal tip attachmentmechanisms which may be used to attach a distal tip to a distal sectionof a probe employed in the devices of the present invention. Each ofthese different distal tip attachment mechanisms causes the distal tipand the distal section of the probe to move through the dense colloidalmaterial of the nucleous pulposus.

FIG. 5A illustrates an embodiment where the distal tip 512 and the neck514 of the distal section is one unit made of the same material. In thisembodiment, the distal tip is rigid relative to the neck 514 of thedistal section.

FIG. 5B illustrates an embodiment where the distal tip 512 and the neck514 of the distal section are attached by a pivot mechanism 516, such asa ball and socket mechanism, which allows the orientation of the distaltip to rotate relative to the neck 514.

FIG. 5C illustrates an embodiment where the distal tip 512 and the neck514 of the distal section are attached by a spring 518. A springmechanism 518 not only allows the distal tip 512 to rotate relative tothe neck 514, the spring mechanism also allows the distal tip to bedistended away from the neck 514.

It is noted with regard to the neck, distal tip and attachmentmechanisms that any combination of the three may be used since it isanticipated that one may wish to alter the navigation behavior of theprobe within the nucleous pulposus by manipulating these threevariables.

FIG. 6 illustrates movement with bending of a distal section 612 withinnucleous pulposus 614 as the probe distal section is advanced within theintervertebral disc. Note that the introducer 620 remains stationary asthe probe is advanced. As can be seen, as the distal section 612 isadvanced, the distal tip 616 and neck 618 are bent away from theintervertebral wall 622. This may be accomplished either by predisposingthe tip and/or neck to bending in a particular direction. It may also beaccomplished by the wall itself having a certain curvature. As the probedistal section is advanced, the distal section bends until the tensioncreated by the bending exceeds the force that is being applied to thedistal section by the tissue to cause the bending. Hence, the rigidityof the flexible distal section limits the amount that the distal sectionultimately bends.

FIGS. 7A-7C illustrate a sequence which shows how tissue force resistingthe forward advancement of the probe within the intervertebral disccauses the distal section of the probe to bend. FIG. 7A shows a probe710 with an asymmetrical distal tip 712. As illustrated, the asymmetryof the tip causes more resistance to be applied to the larger side ofthe asymmetrical distal tip 712. As illustrated in FIG. 7B, theasymmetrical resistance causes the distal section of the probe to bend.As the distal section is advanced further, force begins to be applied tothe back of the distal tip, causing the distal section to bend further.As the distal section is advanced further, more force is applied to thedistal tip 712, as shown by the arrows in FIG. 7C against the distal tip712.

Referring back to FIG. 1E, the longitudinal axis of the introducer 169causes an element extended from the introducer 169 to have a trajectorytoward the center of the disc. However, it is desirable to be able todeploy the probe and any functional elements on the probe adjacent theinternal wall 22 of the annulus fibrosus. FIGS. 8A-8Q illustrate aseries of different embodiments for deploying the distal section of theprobe from the introducer so that the probe approaches the internal wallof the annulus fibrosus.

FIG. 8A illustrates an embodiment where the distal end 812 of the probe814 is attached to the distal end of the introducer 816. As illustratedin FIG. 8B, extension of the distal end 812 of the probe 814 out of thedistal end of the introducer 816 in this embodiment (denoted by thearrow) causes the probe to form a loop. Broadening of the loop byfurther extension of the probe causes the probe to encircle the internalwall 22 of the annulus fibrosus.

FIG. 8C illustrates another embodiment where the distal end 812 of theprobe 814 is attached to the distal end of the introducer 816 via aguide wire lead 818. The guide wire lead 818 is thinner than the probe814 and thus can adopt a smaller radius of curvature than the probe 814.This allows a smaller bore introducer 816 to be utilized or a largerprobe 814 to be utilized since both the distal end of the probe and theguide wire lead can be more readily accommodated within the introducer.As illustrated in FIG. 8D, extension of the distal end 812 of the probe814 out of the distal end of the introducer 816 in this embodiment(denoted by the arrow) causes the probe to form a loop. Broadening ofthe loop by further extension of the probe causes the probe to encirclethe internal wall of the annulus fibrosus.

FIG. 8E illustrates another embodiment where the distal end of the probe814 forms a loop within the introducer where both sides of the probe 814are separately extendable and retractable relative to the distal end ofthe introducer 816. As illustrated in FIG. 8F, extension of the probe814 out of the distal end of the introducer 816 in this embodiment(denoted by the arrow) causes the probe to form a loop. Shown as boxeson the probe are a series of electrodes 820 for delivering energy totissue within the disc. It is noted that other functional elements canalso be positioned on the probe. Broadening of the loop by furtherextension of the probe causes the probe to encircle the internal wall ofthe annulus fibrosus. Extending or retracting one side of the loopshaped probe causes the electrodes to move relative to the inner wall.

FIG. 8G illustrates another embodiment where a guide wire 824 isattached to the distal end of the introducer 816. The guide wire 824 isthinner than the probe 814 and thus can adopt a smaller radius ofcurvature than the probe 814. This allows a smaller bore introducer 816to be utilized or a larger probe 814 to be utilized since both thedistal end of the probe and the guide wire lead can be more readilyaccommodated within the introducer. As illustrated in FIG. 8H, extensionof the guide wire 824 out of the distal end of the introducer 816 inthis embodiment (denoted by the arrow) causes the guide wire 824 to forma loop. Broadening of the loop by further extension of the guide wire824 causes the guide wire 824 to encircle the internal wall of theannulus fibrosus. As illustrated in FIG. 8I, a probe 814 may be extendedalong the guide wire 824 out of the distal end of the introducer. Theprobe 814 may include different functional elements for treating tissuewithin the disc.

FIG. 8J illustrates another embodiment where a guide wire 824 forms aloop within the introducer where both sides of the guide wire loop 824are separately extendable and retractable relative to the distal end ofthe introducer 816. The guide wire 824 is thinner than the probe 814 andthus can adopt a smaller radius of curvature than the probe 814. Thisallows a smaller bore introducer 816 to be utilized or a larger probe814 to be utilized since both the distal end of the probe and the guidewire lead can be more readily accommodated within the introducer. Asillustrated in FIG. 8K, extension of the guide wire 824 out of thedistal end of the introducer 816 in this embodiment (denoted by thearrows) causes the guide wire 824 to form a loop. Broadening of the loopby further extension of the guide wire 824 causes the guide wire 824 toencircle the internal wall of the annulus fibrosus. As illustrated inFIG. 8L, a probe 814 may be extended along the guide wire 824 out of thedistal end of the introducer. The probe 814 may include differentfunctional elements for treating tissue within the disc.

FIGS. 8M-8O illustrate another embodiment of the embodiment shown inFIG. 8J where the guide wire 824 is capable of being folded upon itself.FIG. 8M illustrates the guide wire unfolded where section I includes aguide wire with a thin, concave shape, section II includes a taperedsection that provides an area where the guide wire is folded uponitself, and section III includes a rounded section such that the roundedsection fits within the concave shape of section I. FIG. 8N shows thecross sections of guide wire sections I-III illustrated in FIG. 8M. Asillustrated in FIG. 8O, the guide wire may be folded upon itself wherethe crease is at section II, and section I and section III cometogether. By having sections I and III fit together, the folded guidewire can more readily be accommodated within an introducer.

FIG. 8P provides a sequence illustrating the deployment of the guidewire 824 from an introducer 816 within a disc such that the guide wire824 encircles the internal wall 828 of the disc 830. As illustrated inthe sequence, the crease allows the guide wire loop to be more tightlyfolded together. By then extending one side of the looped guide wire, aside of the guide wire can be expanded. Then, the other side of theguide wire loop may be expanded. The way in which sections I and III fittogether allow for the different sides of the loop to be separatelymoved relative to each other and extended and retracted from theintroducer.

It is noted that although FIG. 8M-8P are described with regard to guidewires, that the probe may also be designed with a crease so that it maybe deployed in a similar manner as shown in FIGS. 8E, 8F and then inFIG. 8P.

FIG. 8Q illustrates yet another embodiment where a guide wire 824 andprobe 814 are used in combination to deploy the probe 814 adjacent aninternal wall 828 of a disc 830. As illustrated, an introducer 816 isintroduced into the disc. A guide wire 824 is then extended from theintroducer 816. The guide wire is predisposed to forming a loop whenextended from the introducer 816 and thus moves toward one side of thedisc. A probe 814 is then extended in combination with the guide wirefrom the introducer 816. The looped distal end of the guide wire 824serves to immobilize the distal end of the guide wire. This then allowsthe probe 814 to be expanded, thereby causing the probe to move alongthe wall of the disc.

It is noted with regard to the above embodiments that the distal portionof the probe and/or the guide wire may be pre-bent, if desired.“Pre-bent” or “biased” means that a portion of the probe, guide wire, orother structural element under discussion, is made of a spring-likematerial that is bent in the absence of external stress but which, underselected stress conditions (for example, while the probe is inside theintroducer), is linear. The un-stressed wire loop diameter preferablyhas a diameter between about 0.025-1 inch, more preferably between about0.05-0.75 inch, or most preferably between about 0.1-0.5 inch. Thediameter of the guide wire preferably has a diameter between about0.005-0.05 inch, more preferably between about 0.007-0.035 inch, or mostpreferably between about 0.009-0.025 inch. Such a biased distal portioncan be manufactured from either spring metal or super elastic memorymaterial (such as Tinel.RTM. nickel-titanium alloy, Raychem Corp., MenloPark Calif.). The introducer (at least in the case of a spring-likematerial for forming the probe) is sufficiently strong to resist thebending action of the bent distal end and maintain the biased distalportion in alignment as it passes through the introducer. Compared tounbiased probes, a probe or guide wire with a biased distal portionencourages advancement of the probe or guide wire substantially in thedirection of the bend relative to other lateral directions. Biasing theprobe or guide wire distal end also further decreases likelihood thatthe distal end of the probe or guide wire will be forced through theannulus fibrosus under the pressure used to advance the probe.

In addition to biasing the distal section of the probe or guide wireprior to insertion into an introducer, the distal section of the probeor guide wire can be provided with a mechanical mechanism for deflectingthe distal section, such as a wire that deflects the distal section inthe desired direction upon application of force to the proximal end ofthe deflection wire. Any device in which bending of the distal end of aprobe or guide wire is controlled by the physician is “activelysettable.” In addition to a distal section that is actively settable byaction of a wire, other methods of providing a bending force at thedistal section can be used, such as hydraulic pressure andelectromagnetic force (such as heating a shaped memory alloy to cause itto contract). Any of a number of techniques can be used to provideselective bending of the probe in one lateral direction.

Optionally, a sheath may be employed in combination with the probe (orguide wire) to facilitate directing movement of the probe within a disc.The sheath can be made of a variety of different materials including butnot limited to polyester, rayon, polyamide, polyurethane, polyethylene,polyamide and silicone.

FIGS. 9A-9C illustrate one embodiment where a sheath having a predefinedcurvature adjacent its distal end introduces curvature to a guide wireor probe extended from the sheath. FIG. 9A illustrates the distal end ofan introducer 912 with a sheath 914 and a probe 916 extending from theintroducer 912. It is noted that a guide wire could be used in place ofthe probe 916, the probe being later drawn over the extended guide wire.

FIG. 9B illustrates the sheath 914 being extended from the distal end ofthe introducer 912. As can be seen, the sheath 914 has a predefinedcurvature 918 adjacent its distal end. This curvature causes the probe916 (or guide wire) to likewise be curved. As illustrated in FIG. 9C,the sheath 914 is only extended a limited distance. Meanwhile, the probeis further extendible relative to the sheath 914. This allows a degreeof curvature to be maintained by the sheath at a known, preselecteddistance that is distal relative to the introducer. Meanwhile, the probe916 can be extended further out of the sheath. The probe itself mayoptionally have its own preselected degrees of curvature.

Since the purpose of the devices of the present invention is to treattissue within an intervertebral disc by operation of the device adjacentto or inside the disc, one or more functional elements may be providedin or on the distal section of the probe to carry out that purpose.

Non-limiting examples of functional elements include any element capableof aiding diagnosis, delivering energy, or delivering or removing amaterial from a location adjacent the element's location in or on theprobe, such as an opening in the probe for delivery of a fluid (e.g.,dissolved collagen to seal the fissure) or for suction, a thermal energydelivery device (heat source), a mechanical grasping tool for removingor depositing a solid, a cutting tool (which includes all similaroperations, such as puncturing), a sensor for measurement of a function(such as electrical resistance, temperature, or mechanical strength), ora functional element having a combination of these functions.

The functional element can be at varied locations on the distal sectionof the probe, depending on its intended use. Multiple functionalelements can be present, such as multiple functional elements ofdifferent types (e.g., a heat source and a temperature sensor) ormultiple functional elements of the same type (e.g., multiple heatsources spaced along the intradiscal portion).

One of the possible functional elements present on the distal section ofthe probe is a thermal energy delivery device. A variety of differenttypes of thermal energy can be delivered including but not limited toresistive heat, radiofrequency (RF), coherent and incoherent light,microwave, ultrasound and liquid thermal jet energies. In theseembodiments, the electrode array length is preferably 0.2-5 inches long,more preferably 0.4-4 inches long, and most preferably 0.5-3 incheslong.

Some embodiments of the device have an interior infusion lumen. Infusionlumen is configured to transport a variety of different media includingbut not limited to electrolytic solutions (such as normal saline),contrast media (such as Conray meglumine iothalamate), pharmaceuticalagents, disinfectants, filling or binding materials such as collagens orcements, chemonucleolytic agents and the like, from a reservoir exteriorto the patient to a desired location within the interior of a disc(i.e., the fissure). Further, the infusion lumen can be used as anaspiration lumen to remove nucleus material or excess liquid or gas(naturally present, present as the result of a liquefying operation, orpresent because of prior introduction) from the interior of a disc. Whenused to transport a fluid for irrigation of the location within thedisc, the infusion lumen is sometimes referred to as an irrigationlumen. Infusion lumen can be coupled to medium reservoir through theprobe.

Optionally, one or more sensor lumens may be included. An example of asensor lumen is a wire connecting a thermal sensor at a distal portionof the probe to control elements attached to a connector in the proximalhandle of the probe.

Energy directing devices may also optionally be included, such asthermal reflectors, optical reflectors, thermal insulators, andelectrical insulators. An energy directing device may be used to limitthermal and/or electromagnetic energy delivery to a selected site of thedisc and to leave other sections of the disc substantially unaffected.An energy directing device can be positioned on an exterior surface ofthe distal section of the probe, as well as in an internal portion ofthe probe. For example, energy can be directed to the walls of a fissureto cauterize granulation tissue and to shrink the collagen component ofthe annulus, while the nucleus is shielded from excess heat.

Therapeutic and/or diagnostic agents may be delivered within the discvia the probe. Examples of agents that may be delivered include, but arenot limited to, electromagnetic energy, electrolytic solutions, contrastmedia, pharmaceutical agents, disinfectants, collagens, cements,chemonucleolytic agents and thermal energy.

In one embodiment, the device includes markings which indicate to thephysician how far the probe has been advanced into the nucleus. Such avisible marking can be positioned on the handle or on the flexibletubing. Preferred are visible markings every centimeter to aid thephysician in estimating the probe tip advancement.

If desired, visible markings can also be used to show twisting motionsof the probe to indicate the orientation of the bending plane of thedistal portion of the probe. It is preferred, however, to indicate thedistal bending plane by the shape and feel of the proximal end of theprobe assembly. The probe can be attached to or shaped into a handlethat fits the hand of the physician and also indicates the orientationof the distal bending plane. Both the markings and the handle shape thusact as control elements to provide control over the orientation of thebending plane; other control elements, such as plungers or buttons thatact on mechanical, hydrostatic, electrical, or other types of controls,can be present in more complex embodiments of the invention.

Additionally, a radiographically opaque marking device can be includedin the distal portion of the probe (such as in the tip or at spacedlocations throughout the intradiscal portion) so that advancement andpositioning of the intradiscal section can be directly observed byradiographic imaging. Such radiographically opaque markings arepreferred when the intradiscal section is not clearly visible byradiographic imaging, such as when the majority of the probe is made ofplastic instead of metal. A radiographically opaque marking can be anyof the known (or newly discovered) materials or devices with significantopacity. Examples include but are not limited to a steel mandrelsufficiently thick to be visible on fluoroscopy, a tantalum/polyurethanetip, a gold-plated tip, bands of platinum, stainless steel or gold,soldered spots of gold and polymeric materials with radiographicallyopaque filler such as barium sulfate. A resistive heating element or anRF electrode(s) may provide sufficient radio-opacity in some embodimentsto serve as a marking device.

FIGS. 10A-10C illustrate a series of preferred designs for bipolarthermal energy delivery devices which may be used in combination withthe devices of the present invention. It is noted that radio frequencyenergy or resistive heating may be performed using these designs.

FIG. 10A illustrates an embodiment where the thermal energy deliverydevice is a bipolar electrode comprising an active electrode 1012 and areturn electrode 1014 where the active electrode 1012 and returnelectrode 1014 are each spirally wrapped around a portion of the distalsection of the probe 1016. The probe is shown to be extending from anintroducer 1018. When a potential is introduced between the activeelectrode 1012 and return electrode 1014, current flows through thetissue adjacent the two electrodes. Since the two electrodes are wrappedin a spiral about the active electrode, energy transfer is distributedalong the length of the probe, thereby more evenly heating the adjacenttissue.

It is noted that the distal section of the probe 1016 shown in FIG. 10Ais predisposed to form a loop. By sizing the loop to approximate theinner diameter of an intervertebral disc, it is possible to cause theloop shaped probe to abut the internal wall of the disc. Then, byapplying a potential between the electrodes, energy can be somewhatuniformly delivered to tissue adjacent the internal wall of the disc. Itis noted that over time, tissue interior to the loop may also beuniformly treated by the loop shaped electrode.

FIG. 10B illustrates another embodiment of a thermal energy deliverydevice. Like the embodiment shown in FIG. 10A, the distal section of theprobe 1016 is predisposed to form a loop. By sizing the loop toapproximate the inner diameter of an intervertebral disc, it is possibleto cause the loop shaped probe to abut the internal wall of the disc. Asillustrated in FIG. 10B, an active electrode 1012 and a return electrode1014 are positioned on opposing sides of the loop. By applying apotential between the electrodes, energy can be delivered to tissuepositioned between the two electrodes.

FIG. 10C illustrates another embodiment of a thermal energy deliverydevice. Like the embodiment shown in FIGS. 10A and 10B, the distalsection of the probe 1016 is predisposed to form a loop. As illustrated,a series of alternating active 1012 and return 1014 electrodes arepositioned along the distal section of the probe. By applying apotential between the series of active and return electrodes, energy canbe delivered to tissue along the length of the probe.

FIGS. 11A and 11B illustrate yet another embodiment for a thermal energydelivery device which may be used in combination with the devices of thepresent invention. It is noted that radio frequency energy or resistiveheating may be performed using these designs.

FIG. 11A illustrates an embodiment where a pair of probes which form anactive electrode 1112 and a return electrode 1114 extend from anintroducer or sheath 1116 and are spaced apart from each other. Byapplying a potential between the active and return electrodes, energycan be delivered to tissue along the length of the probes.

FIG. 11B illustrates a variation on the embodiment shown in FIG. 11Awhere the pair of probes which form an active electrode 1112 and areturn electrode 1114 diverge from each other adjacent their distalends. By applying a potential between the active and return electrodes,energy can be delivered to tissue along the length of the probes. Byhaving the two probes diverge, a larger area of tissue may be treated.

Also shown in FIGS. 11A and 11B is a thermocouple 1118 for sensingtemperature and a feedback loop 1120 for regulating the potentialbetween the electrodes in response to measurements by the thermocouple.

It is noted that other energy delivery devices may also be used with theintervertebral disc treatment devices of the present invention beyondthose described with regard to FIGS. 10A-C and 11A-B, including thosedescribed in U.S. Pat. Nos. 6,135,999; 6,126,682; 6,122,549; 6,099,514;6,095,149; 6,073,051; 6,007,570; 5,980,504, which are each incorporatedherein by reference.

When the device is used as a resistive heating device, the amount ofthermal energy delivered to the tissue is a function of (i) the amountof current passing through heating element, (ii) the length, shape,and/or size of heating element, (iii) the resistive properties ofheating element, (iv) the gauge of heating element, and (v) the use ofcooling fluid to control temperature. All of these factors can be variedindividually or in combination to provide the desired level of heat.Power supply associated with heating element may be battery based. Theprobe can be sterilized and may be disposable.

In some embodiments, thermal energy is delivered to a selected sectionof the disc in an amount that does not create a destructive lesion tothe disc, other than at most a change in the water content of thenucleus pulposus. In one embodiment there is no removal and/orvaporization of disc material positioned adjacent to an energy deliverydevice positioned in a nucleus pulposus. Sufficient thermal energy isdelivered to the disc to change its biochemical and/or biomechanicalproperties without structural degradation of tissue.

Thermal energy may be used to cauterize granulation tissue which is painsensitive and forms in a long-standing tear or fissure. Additionally oralternatively, thermal energy is used to seal at least a part of thefissure. To do that, the disc material adjacent to the fissure istypically heated to a temperature in the range of 45-70 degree C. whichis sufficient to shrink and weld collagen. In one method, tissue isheated to a temperature of at least 50 degree C. for times ofapproximately one, two, three minutes, or longer, as needed to shrinkthe tissue back into place.

Delivery of thermal energy to the nucleus pulposus removes some waterand permits the nucleus pulposus to shrink. This reduces a “pushing out”effect that may have contributed to the fissure. Reducing the pressurein the disc and repairing the fissure may help stabilize the spine andreduce pain.

Global heating of the disc also can be used to cauterize the granulationtissue and seal the fissure. In this embodiment of the method, theheating element is positioned away from the annulus but energy radiatesto the annulus to raise the temperature of the tissue around thefissure. This global heating method can help seal a large area ormultiple fissures simultaneously.

FIG. 12 shows an embodiment of the guide wire 1224 with a mechanism 1235at the end of the distal portion 1212 of the guide wire for attachingthe guide wire to the inner wall of the intervertebral disc. Byattaching the attachment mechanism to the inner wall, displacement ofthe guide wire is prevented during subsequent exchange and withdrawal ofother system components. The guide wire 1224 is extended into theintervertebral disc and navigated to a desired portion along the innerwall of the disc. The attachment mechanism is inserted and held in placesuch that the distal portion 1212 is attached to the inner wall tissue.As illustrated in FIG. 12, extension of the probe 1214 over the guidewire into the nucleus 120 of the intervertebral disc causes the probe tomove along the path of the guide wire. The attachment of the guide wireto the inner wall assists in keeping the guide wire in place despiteforce on the guide wire by the probe. In the instance illustrated, thedistal portion 1231 of the probe 1214 is positioned at an annularfissure 44 for performing a function as described herein. Allpublications and patent applications mentioned in this specification areherein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

While the present invention is disclosed with reference to preferredembodiments and examples detailed above, it is to be understood thatthese examples are intended in an illustrative rather than limitingsense, as it is contemplated that modifications will readily occur tothose skilled in the art, which modifications will be within the spiritof the invention and the scope of the appended claims. Any patents,papers, and books cited in this application are to be incorporatedherein in their entirety.

We claim:
 1. An intervertebral disc device comprising: a sheathconfigured to be extended into an intervertebral disc from an introducerthat is percutaneously delivered into an interior of the intervertebraldisc, the sheath being predisposed to adopting a bent configuration whenextended from the introducer; a probe adapted to be extended from thesheath, the sheath causing the probe to adopt a bent configuration; anda handle coupled to the probe for guiding the probe within theintervertebral disc.
 2. An intervertebral disc device according to claim1 wherein a distal section of the probe comprises a flexible neck whichtapers in a proximal to distal direction, and a distal tip which islarger in cross sectional diameter than the flexible neck adjacent thedistal tip, the flexible neck and distal tip serving to prevent theprobe distal end from piercing an internal wall of the intervertebraldisc.
 3. An intervertebral disc device according to claim 2 wherein theflexible neck is not predisposed to bending in any direction relative toa longitudinal axis of the probe.
 4. An intervertebral disc deviceaccording to claim 2 wherein the flexible neck is predisposed to bendingalong a single plane relative to a longitudinal axis of the probe.
 5. Anintervertebral disc device according to claim 2 wherein the flexibleneck is predisposed to bending in opposing directions along a singleplane relative to a longitudinal axis of the probe.
 6. An intervertebraldisc device according to claim 2 wherein the distal tip is symmetricalabout a longitudinal axis of the probe.
 7. An intervertebral disc deviceaccording to claim 2 wherein the distal tip is asymmetrical about alongitudinal axis of the probe.
 8. An intervertebral disc deviceaccording to claim 2 wherein the distal tip has a flat surfaceperpendicular to a longitudinal axis of the probe.
 9. An intervertebraldisc device according to claim 2 wherein the distal tip is attached tothe neck of the probe by a pivot mechanism.
 10. An intervertebral discdevice according to claim 2 wherein the distal tip is attached to theneck of the probe by a ball and socket mechanism.
 11. An intervertebraldisc device according to claim 2 wherein the flexibility of the neck ofthe probe causes the probe to bend and the distal tip to trail behind aportion of the probe as the probe is advanced through tissue within anintervertebral disc.
 12. An intervertebral disc device according toclaim 1 wherein a distal section of the probe comprising one or moreactive electrodes and one or more return electrodes which are positionedon the probe such that there are multiple pairs of an active band and areturn band of the active and return electrodes adjacent each otherpositioned longitudinally along the length of the distal section of theprobe, the electrodes being adapted to deliver bipolar electromagneticenergy to tissue within the intervertebral disc.
 13. An intervertebraldisc device according to claim 12 wherein the distal section of theprobe is predisposed to forming a loop.
 14. An intervertebral discdevice according to claim 1 wherein a distal section of the probe ispredisposed to forming a loop when extended from the distal end of theintroducer, the looping portion of the probe comprising an activeelectrode and a return electrode which are positioned on the probe suchthat the active and return electrodes are on opposing sides of the probeloop.
 15. An intervertebral disc device according to claim 1 wherein adistal section of the probe comprises separate active and returnelectrode elements which are predisposed to bending away from each otherwhen extended from the distal end of the introducer.
 16. Theintervertebral disc device according to claim 1 wherein: a distalsection of the sheath is predisposed to adopting the bent configuration,and the bent distal section of the sheath causes the probe to adopt thesame bent configuration.
 17. The intervertebral disc device according toclaim 1 wherein the probe is adapted to be extended from a distal end ofthe sheath.
 18. The intervertebral disc device according to claim 1wherein: a section of the sheath is predisposed to adopting the bentconfiguration, and the sheath causes the probe to adopt the same bentconfiguration inside of the section when the section has adopted thebent configuration.
 19. The intervertebral disc device according toclaim 1 wherein the sheath is mechanically predisposed to adopting thebent configuration inside of the intervertebral disc.
 20. Theintervertebral disc device according to claim 1 further comprising theintroducer.
 21. An intervertebral disc device comprising: a sheathconfigured to be extended into an intervertebral disc from an introducerthat is percutaneously delivered into an interior of the intervertebraldisc, the sheath being predisposed to adopting a bent configuration whenextended from the introducer; a guide wire adapted to be extended fromthe sheath, the sheath causing the guide wire to adopt a bentconfiguration; a probe adapted to be extended from the sheath over theguide wire, the sheath causing the probe to adopt a bent configuration;and a handle coupled to the probe for guiding the probe within theintervertebral disc.
 22. An intervertebral disc device according toclaim 21 wherein a distal section of the probe comprising one or moreactive electrodes and one or more return electrodes which are positionedon the probe such that there are multiple pairs of an active band and areturn band of the active and return electrodes adjacent each otherpositioned longitudinally along the length of the distal section of theprobe, the electrodes being adapted to deliver bipolar electromagneticenergy to tissue within the intervertebral disc.
 23. An intervertebraldisc device according to claim 22 wherein the distal section of theprobe is predisposed to forming a loop.
 24. An intervertebral discdevice according to claim 21 wherein a distal section of the probe ispredisposed to forming a loop when extended from the distal end of theintroducer, the looping portion of the probe comprising an activeelectrode and a return electrode which are positioned on the probe suchthat the active and return electrodes are on opposing sides of the probeloop.
 25. An intervertebral disc device according to claim 21 wherein adistal section of the probe comprises separate active and returnelectrode elements which are predisposed to bending away from each otherwhen extended from the distal end of the introducer.
 26. A methodcomprising: extending a sheath into an interior of an intervertebraldisc through an introducer, the sheath adopting a predisposed bentconfiguration at a point that is distal to the introducer; and extendinga probe through the sheath such that the probe adopts a bentconfiguration distal to the introducer as the probe extends through theextended section of the sheath.
 27. The method of claim 26 furthercomprising performing electrosurgery with an electrode positioned on adistal portion of the probe.
 28. A method comprising: extending a sheathinto an interior of an intervertebral disc through an introducer, thesheath adopting a predisposed bent configuration at a point that isdistal to the introducer; extending a guide wire through the sheath suchthat the guide wire adopts a bent configuration distal to the introduceras the guide wire extends through the extended section of the sheath;and extending a probe over the guide wire through the sheath such thatthe probe adopts a bent configuration distal to the introducer as theprobe extends through the extended section of the sheath.
 29. The methodof claim 28 further comprising performing electrosurgery with anelectrode positioned on a distal portion of the probe.